Clock spring anchoring means



p 50 F. FENGLER w2,522,107

CLOCK SPRING-ANCHORING MEANS Filed May 7, 1946 y w W M ATTORNEY Patented Sept. 12, 1950 7 2,522,107 CLOCK SPRING ANCHORING MEANS Ferdinand Fengler, Bristol, Comm, assignor to The E. Ingraham Company, Bristol, Conn., a corporation of Connecticut Application May 7, 1946, Serial No. 667,931

The present invention relates in general to timepieces and more especially to improved means for securing the main and alarm springs of a'timepiece to the frame.

Heretofore, the free or outer ends of the mainsprings and alarm springs of timepieces have been made fast to the frames by fastening-means comprising, almost universally, a separate clamp 01' a clamp formed integrally on the outer end of the spring and secured to one of the pillars of the frame by a rivet or similar type of fasteningmeans. This construction is not only relatively expensive but necessitates that the entire frame be disassembled to replace a broken spring.

An object of the invention is to provide, improved means for anchoring the outer or free ends of the main and alarm springs of a timepiece to the frame.

A further object is to provide improved mainspring fastening-means to enable the spring to be engaged with and disengaged from'the frame of the timepiece without disassembling the frame.

A still further object is to provide an aperture in the outer end of a timepiece spring adapted to engage over a projection on the frame to anchor the spring to the frame.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. l is a fragmentary plan view of the frame of a timepiece embodying the improved springanchoring means of this invention;

Fig. 2 is a front elevation of the frame showing the spring-anchoring means in Fig. 1;

Fig. 3 is a sectional view on line 3-3 of Fig. 1; and

Fig. 4 is a modification.

Referring to the drawings which illustrate an exemplary embodiment of the invention, the timepiece-frame is indicated generally at In and comprises front and rear movement-plates l I and I2 held in spaced parallel relationship by pillars l3. Mounted between the front and rear movement-plates are gear -trains comprising a timetrain indicated generally at M and an alarmtrain I 5. The time-train I4 is of conventional construction and is driven by the force of a wound spiral mainspring such as shown at It, the latter being supported on a winding-arbor I! which is 3 Claims. (01. 5s 52) rotatably mounted at its opposite ends in the front and rear movement-plates. The rear extremity of the winding-arbor I! is provided With the usual winding-key It for manually rotating the arbor I 'l. The mainspring I6 is secured at its inner end 19 to the winding-arbor ll, the connection between the inner end of the spring and the arbor being the usual type of fastening-means 20, as shown in Fig. 3.

The opposite or outer free end 2| of the mainspring l6 is adapted to be anchored to the frame ill in a manner such as to enable the outer end 2| of the spring to be readily attached thereto and removed therefrom with dispatch and without necessitating the disassembly of the entire frame. To this end, the outer extremity 2| of the mainspring is reduced in width as shown in Fig. 3, the reduced portion constituting a tongue 22 having a radius at its outer end and a longitudinal slot 23. The slot 23 is substantially rectangular, its longitudinal axis being coincident with the longitudinal axis of the tongue 22.

v The frame ll] of the timepiece is provided with a projection 24 which is an integral extension of the rear movement-plate I2. The projection comprises an enlarged head-portion 26 connected to the rear movement-plate l2 by a reduced neckportion 21, the inner and outer edges of which constitute two substantially V-shaped notches 28 and 29 the outwardly-diverging walls of each notch forming shoulders 30 and 3|, respectively. The width and length of the slot 23 in the outer extremity of the mainspring correspond substantially to the thickness and width respectively of the head-portion 26 of the frame-projection 24, as a consequence of which the slotted end of the spring is adapted to be slipped over the headportion 26 and to engage against the inner shoulders 30 and 3| of the respective notches 28 and 29. Since the length of the slot 23 is greater than the width of the neck-portion 21 of the projection 24, the force of the wound mainspring l6, which normally tends to move the outer free end 2| thereof in a direction to unwind the mainspring, acts to pull the free end of the spring inwardly, as seen in Fig. 1 whereby the outer end of the slot 23 is shifted into the bottom of the outer notch 28, asv shown in Fig. 3. The outer end of the spring is thus engaged between the outwardlydiverging shoulders 30 of the notch 28, thus effectively anchoring the slotted-end of'the spring to the frame without requiring the use of rivets, sleeves or any other additional securing means. The slotted-end of the spring may be readily slipped off of the projection 24 without separating the front and rear movement-plates II and [2 respectively of the frame, simply by pulling the free end of the spring in a direction counter to its normal bias so as to move the outer end of the slot 23 over the left-hand shoulder 30 of the outer notch 28, as seen in Fig. 1.

A further application of the slotted-spring structure is illustrated in Fig. 4 wherein the projection 24a of the rear movement-plate |2a comprises a tongue-shaped extension having substantially-parallel inner and outer edges 28a: and 29a respectively, and a circular outer end 32a. A shoulder am is formed at the junction of the inside edge 29a of the extension with the rearplate I2a of the frame. The width of theslot 23a in the free end of the spring 22a is substantially equal to the width of the tongue-element 24a, as a consequence of which the free end of the spring may be slipped over the tongue 24a and moved up into engagement with the shoulder 3la. Normally, the force of the wound or partially-wound mainspring acting to pull the free end of the spring in a counterclockwise direction, as seen in Fig. 4, binds the slotted free end of the spring on the tongue 240; so as to effectively anchor the free end of the spring thereto. As a precaution against any possibility of the free end of the spring slipping off of the tongue-shaped extension Ma, the pillar 53a at this corner of the frame of the timepiece is supported in an aperture in the outer end of the extension 24a so that the nut 33 and spacingcollar 34 on the upper end of the pillar, are located adjacent the outsid face of the free end of the spring and thus positively prevent accidental removal of the free end of the spring from the extension 24a.

Although the description relates in particular to the mainspring fastening-means of a timepiece, it will be understood that a similar type of fastening-means is applicable to the alarm spring of timepieces embodying an alarm-train.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present em bodinients are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. In a timepiece having a frame comprising front and rear movement-plates, a gear-train, a spring for driving said gear-train, said spring having a substantially-rectangular slot in its outer end, a spring-winding arbor and means to secure the inner end of said spring to said arbor; of a projection on the said rear move ment-plate the cross-sectional dimensions of said projection being substantially equal to the diinensions of said rectangular slot to permit said projection to make a snug fit in said aperture so as to secure the said outer end of said spring to said frame; and a pillar supported in the outer end of said projection adjacent the outer face of the free end of said spring to positively keep th free end of said spring on said projection.

2. In a timepiece, the combination including: a frame having spaced parallel front and rear movement-plates; a gear-train; a spring driving said gear-train, said spring being formed with 4 v a reduced tongue-portion at its outer end having a substantially-rectan lar slot therein extending longitudinally thereof; a spring-winding arbor arranged to support said spring between said front and rear movement-plates in spaced substantially-parallel relationship thereto; means to secure the inner end of said spring to said arbor; a projection on one of said movementplates, the plane intersecting the opposite edges of said projection coinciding with the plane of the said one movement-plate, the plane of said projection being also substantially perpendicular to a plane intersecting the opposite edges of said tongue, the width of said projection being substantially equal to the length of said rectangular slot so as to engage therein with a substantiallyclose fit with the end of said projection extending outwardly beyond the slotted tongue of said spring; and means on the outwardly-extending end of said projection immediately adjacent the outer face of said slotted tongue to positively retain the slotted end of said tongue on said projection.

3. In a timepiece, the combination including: a frame having spaced parallel front and rear movement-plates; a gear-train; a spring for driving said gear-train, said spring being formed with a reduced tongue-portion at its outerend having a substantially-rectangular slot therein extending longitudinally thereof; a spring-winding arbor arranged to support said spring between said front and rear movement-plates in spaced substantially-parallel relationship thereto; means to secure the inner end of said spring to said arbor; a projection onone of the said movementplates, the plane intersecting the opposite edges of said projection coinciding with the plane of the said one movement-plate, the said plane of said projection being also substantially perpendicular to a plane intersecting the opposite edges .Of said tongue, said projection comprising an enlarged head-portion joined integrally to the edge .of the said one movement-plate by a reduced neck-portion symmetrical with respect to said head-portion and forming spring-retaining shoulders therewith and with the corresponding edge of the said one movement-plate, the crosssectional dimensions of said head-portion being substantially equal to the corresponding dimensionsof said rectangular slot to permit the slotted tongue of said spring to be slipped over said enlarged head-portion into engagement with the said reduced neck-portion of said projection, the said spring-retaining shoulders thereof being arranged to positively retain said slotted tongue on saidreduced neck-portion. FERDINAND FENGLER.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 1,435,642 Horn Nov. 14, 1922 FOREIGN PATENTS Number Country Date.

17,476 Great Britain Aug. 31, 1901 73,814 Switzerland Dec. 1, 1916 625,085 France Apr. 19, 1927 

